基于大容量阵列光栅振动传感机理的地铁隧道地面入侵监测技术研究

Study on Subway Tunnel Intrusion Monitoring Based on High Capacity Distirbuted Array Grattings Vibration Sensing Technology

为防止外部非法入侵事件造成地铁隧道结构损伤,确保运营安全,实时在线监测地铁隧道沿线地面施工侵扰尤为重要。作者研发了基于大容量阵列光栅分布式振动传感机理的全时全域地铁隧道入侵监测系统。设计了外部入侵模拟实验,在选定的地面区域,液压挖掘机以离散和连续脉冲两种不同加载模式及强度在距离测振光缆5种不同距离范围敲击地面模拟外部入侵,记录位于地铁隧道洞壁及隧道道床的分布式振动光缆的振动响应信号。通过分析入侵过程中关键时刻的现场记录及振动光缆的振动响应,提出了一种基于大容量分布式光纤光栅结构振动响应的监测方法,可用于检测地铁隧道地面入侵事件,定位入侵地面区域,区分入侵强度和模式。

In order to ensure the safety of subway tunnel structure and prevent illegal intrusion events such as road construction above the tunnel,it is very important to realize real-time on-line monitoring of the construction intrusion.In this paper,an intrusion monitoring system for metro tunnels based on high capacity distributed vibration sensing mechanism of array gratings is investigated.A simulated experiment of the ground intrusion along the selected path was designed and implemented,in which a hydraulic excavator was chosen to exert the external intrusion with two different modes and strength at five slected intrusion sites.In each intrusion site the discrete and continuous pulse were detected by the measuring optic cables which located on the tunnel wall and tunnel track bed.The response signals of distributed vibration optical cables are recorded by the two different cables.By checking the on-site records of the critical time in the intrusion process,aground intrusion detection system based on high capacity distributed structural vibration response is proposed,which can locate the intrusion area and distinguishe the intrusion intensity from the typical pertubation modes.